[gigatexal]

Another approach could be to create the materialized view and then use some sort of event system say the pg_notify subsystem to capture an event and then increment some aggregation -- this would eliminate the need for scheduled view refreshes and keep the view almost real-time and quick.

[udfalkso]

This might be best done using triggers. I've had good experiences with the Hair Trigger gem for managing these in rails.

[gigatexal]

Trigger would work. But going the pg_notify approach could allow for asynchronous updating whereas the trigger approach could slow writes.

[erik_seaberg]

Real-time means latency is predictably within some deadline. But the system he describes is returning wrong answers quickly rather than invalidating stale cache hits and recomputing right answers too slowly.

[swanson]

You could do something similar with built-in ActiveRecord callbacks as well.